Effects of oral contrast on dose in abdominopelvic computed tomography with pure iterative reconstruction

• 作者: Fiachra Moloney Kevin P Murphy Lee Crush Liam J Healy Maria Twomey Michael M Maher Owen J O’Connor Sylvia Sexton
• 来源期刊: 世界放射学杂志：英文版（电子版）
• 学科: 医学
• 关键词: Radiation DOSE Low DOSE COMPUTED TOMOGRAPHY ABDOMINAL imaging Oral CONTRAST COMPUTED TOMOGRAPHY
• 年，卷（期）: 2016,（9）
• 页码范围: 809-815
• 页数: 7页
• 分类号: R574

摘要

AIM To assess the effect of neutral(NC) and positive(PC) oral contrast use on patient dose in low-dose abdominal computed tomography(CT).METHODS Low-dose clinically indicated CTs were performed on 79 Crohn’s patients(35 = PC, 1 L 2% gastrografin; 44 = NC, 1.5 L polyethylene glycol). Scanner settings for both acquisitions were identical apart from 25 s difference in intravenous contrast timing. Body mass index(BMI), scan-ranges, dose-length product and size-specific dose estimated were recorded. Data was reconstructed with pure model-based iterative reconstruction. Image quality was objectively and subjectively analysed. Data analysis was performed with Statistical Package for Social Scientists.RESULTS Higher doses were seen in neutral contrast CTs(107.60 ± 78.7 m Gy.cm, 2.47 ± 1.21 m Gy vs 85.65 ± 58.2 m Gy.cm, 2.18 ± 0.96 m Gy). The differencehad both NC and PC investigations. Image-quality assessment yielded 6952 datapoints. NC image quality was significantly superior(P < 0.001)(objective noise, objective signal to noise ratio, subjective spatial resolution, subjective contrast resolution, diagnostic acceptability) at all levels. NC bowel distension was significantly(P < 0.001) superior.CONCLUSION The use of polyethylene glycol as a neutral OC agent leads to higher radiation doses than standard positive contrast studies, in low dose abdominal CT imaging. This is possibly related to the osmotic effect of the agent resulting in larger intraluminal fluid volumes and resultant increased overall beam attenuation.